This invention relates to a capstan drive motor in which a thrust pad is provided between a locking member and a bearing on the motor shaft.
A conventional electric motor of this type is shown in FIG. 4, wherein a boss 3 to the periphery of which a rotor yoke 2 is secured is fitted on the base end of the shaft 1 of the capstan motor of a VTR or tape recorder. The rotor yoke 2 is cup-shaped, and a cylindrical rotor magnet 4 is provided on its inner wall. The rotor magnet 4 confronts the outer periphery of a stator core 6 having windings 5 wound on protruding poles thereof (not shown). The stator core 6 is fixedly mounted on a bearing holder 7 such that the central hole of the stator core is engaged with the outer wall of the bearing holder 7. Oil-impregnated metal bearings 8 are fitted in the upper and lower ends of the inner wall of the bearing holder and the shaft 1 is rotatably inserted into the holes of the bearings. A flange 7a extends from the outer wall of the bearing holder, to support a circuit board 9 including a control circuit, drive circuit, etc. The board 9 is secured to a cup-shaped housing 10 with screws 11. A thrust pad 12 is provided at the center of the housing and abuts against the base end of the shaft 1 to prevent its downward movement. An annular groove 3a is formed in the outer wall of the boss 3, and accommodates an endless belt 13 of a drive reel or the like.
In such a conventional motor construction, the thrust pad 12 and housing 10 thwart the miniaturization of the motor, and attendantly the compactness of the recorder in which the motor is installed. In the case of a capstan motor of the type wherein a reel stand is driven by the belt 13, the housing 10 must be mounted to the board 9 after the belt is reeved around the boss groove 3a, which impedes the mounting of the housing and can score or damage the belt.